Normal Operation; Compressor Control; Eev( Electronic Expansion Valve) Control - LG CT09F Service Manual

1. Normal operation

Basic principle is to control the rpm of the motor by changing the working frequency of the compressor.
Three phase voltage is supplied to the motor and the time for which the voltage will supplied is controlled by IPM
(intelligent power module).
Switching speed of IPM defines the variable frequency input to the motor.
Actuator
Compressor
Fan
EEV

2. Compressor control

Fuzzy control : Maintain evaporating temperature (Te) to be constant on cooling mode and constant condensing temper-
ature (Tc) on heating mode by fuzzy control to ensure the stable system performance.

3. EEV( Electronic Expansion Valve) control

EEV operates with fuzzy control rules to keep the target temperature of discharge pipe.
＊Cooling mode
* Cooling / Heating mode
The target temperature of discharge pipe :
• T : Theoretical discharge temperature
d
• T : T (current evaporating temperature) + T
1 e
• P : Absolute High pressure (kPa)
high
• P : Absolute low pressure (kPa)
low
Cooling operation
Fuzzy control
Fuzzy control
Discharge Temp. Control
Inverter linear control as cooling and heating load increasing
P
high
T = T
d 1
P
low
(Suction Superheating temperature)
SSH
- 50 -
Heating operation
Fuzzy control
Fuzzy control
Discharge Temp. Control
Linear control
Cooling and heating load
( n ) 1
n
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Part 3 Basic Control
Stop state
Stop
Stop
Min. Pulse